Uptesting is moving folks to /external/robolectric from /external/robolectric-shadows

This commented out line references the old robolectric ("Robolectric_all-target") which is being replaced by Robolectric_all-target_upstream

Bug: 314757990
Test: none, this is simply removing a commented out dep.
Flag: NA
Change-Id: I25eed6cef457bada06289656745ca5b5286bb467